Send your comments directly to PTB by using the Submit a Request link at the top of the page. It would also help if you would be specific in the problems you are having, rather than general complaints.

I've been a Finale user since version 3 ...

Me too even before V3.

...many of the things I use in Finale that had previously worked well, now have strange changes ...

Like what for instance? I use Finale almost every day and have completed four concert band pieces. Finale 27 on Windows 10 has performed almost flawlessly since I installed it. On both the laptop and Dell desktop which I use 90% of the time.. I had to update a sound driver that was ancient but that is it. From what I have read using a Mac can be somewhat flakey so perhaps that is the root of the issues you see. I would submit a tech request and tell them exactly what the issues are. For the most part they are very helpful in my experience, maybe a little slow but pretty good.

Until the current MacOS 12 Monterey, 27 was working great for me. Now it isn't so I've reverted back to 26 till 27 gets sorted out. 

As long as my work gets done…